The weekly decline in oil prices was recorded for the first time since the week ended October 30.
The largest drop is predicted for projects in the Permian Basin.
The cost of February Brent futures on the London ICE Futures exchange on Friday is $50.34 per barrel.
Brent rose to $49.08 despite the largest increase in US inventories since April.
This year Iran sold an average of 600 to 700 thousand barrels of oil per day.
The police are confident that people who work or are associated with the oil sector may try to recruit sources of information for intelligence services.
The situation with oil prices has not demonstrated stability over the past 4 months.
Over the past week, world oil quotations have experienced serious volatility.
After trading on September 16, the futures of benchmark oil, Brent and WTI increased by 12.4% and 14.7% respectively
U.S. petroleum and natural gas production increased by 16% and by 12%, respectively, in 2018.